A Review of Optical Fiber Sensing Technology Based on Thin Film and Fabry–Perot Cavity

Abstract

Fiber sensors possess characteristics such as compact structure, simplicity, electromagnetic interference resistance, and reusability, making them widely applicable in various practical engineering applications. Traditional fiber sensors based on different microstructures solely rely on the thermal expansion effect of silica material itself, limiting their usage primarily to temperature or pressure sensing. By employing thin film technology to form Fabry–Perot (FP) cavities on the end-face or inside the fiber, sensitivity to different physical quantities can be achieved using different materials, and this greatly expands the application range of fiber sensing. This paper provides a systematic introduction to the principle of FP cavity fiber optic sensors based on thin film technology and reviews the applications and development trends of this sensor in various measurement fields. Currently, there is a growing need for precise measurements in both scientific research and industrial production. This has led to an increase in the variety of structures and sensing materials used in fiber sensors. The thin film discussed in this paper, suitable for various types of sensing, not only applies to fiber optic FP cavity sensors but also contributes to the research and advancement of other types of fiber sensors.

Optical Fiber Temperature and Humidity Dual Parameter Sensing Based on Fiber Bragg Gratings and Porous Film

“…Due to the fact that the high-order reflective light is extremely weak, the light interference of the thin film can be simplified as a dual-beam interference. The total reflective light intensity of the dual-beam interference can be expressed as Formula (8) [28]:…”

High-resolution optical vector analysis based on single sideband modulation using a dual port Mach–Zehnder modulator

“…[4][5][6] As a high-quality optical device with near-IR wavelength, Fabry-Perot (FP) cavity has been developed rapidly and widely used in recent years, and which has been put into use in the optical fiber sensing technology, supercapacitor technology and light modulators. [7][8][9] In order to accelerate the development and application of FBGs and the FP cavities, the frequency responses need to be measured in high-resolution and high-accuracy.…”

Experimental Investigation of optical fiber Fabry-Perot resonators: resonance enhancement through reflective coatings and concave mirrors

“…Fabry-Perot (F-P) resonator is one of the most popular type of optical resonators, which found numerous applications in various optical instruments, including laser cavities, spectrometers and sensors. Since the traditional free-space F-P resonators has been extensively studied and characterized through last decades [1], [2], [3], the developed theory behind them does not accurately apply to now emerging optical-fiber-based F-P resonators [4], [5], [6], [7]. The fact that the beam emitted from an optical fiber experiences divergence and that the light after each roundtrip needs to meet the condition of the acceptance cone of the fiber, makes the operation of optical fiber F-P resonator distinct from the operation of standard F-P [8].…”